Method and system for weighted fair flow control in an asynchronous metro packet transport ring network

Abstract

A method and system for implementing weighted fair flow control on a metropolitan area network. Weighted fair flow control is implemented using a plurality of metro packet switches (MPS), each including a respective plurality of virtual queues and a respective plurality of per flow queues. Each MPS accepts data from a respective plurality of local input flows. Each local input flow has a respective quality of service (QoS) associated therewith. The data of the local input flows are queued using the per flow queues, with each input flow having its respective per flow queue. Each virtual queue maintains a track of the flow rate of its respective local input flow. Data is transmitted from the local input flows of each MPS across a communications channel of the network and the bandwidth of the communications channel is allocated in accordance with the QoS of each local input flow. The QoS is used to determine the rate of transmission of the local input flow from the per flow queue to the communications channel. This implements an efficient weighted bandwidth utilization of the communications channel. Among the plurality of MPS, bandwidth of the communications channel is allocated by throttling the rate at which data is transmitted from an upstream MPS with respect to the rate at which data is transmitted from a downstream MPS, thereby implementing a weighted fair bandwidth utilization of the communications channel.

Description

FIELD OF THE INVENTION[0001]The present invention relates to the field of asynchronous metro packet transport ring networks. More specifically, the present invention pertains a data flow control method and system for managing the data flow with respect to the available bandwidth in a metro packet transport ring network.BACKGROUND ART[0002]The Internet is a general purpose, public computer network which allows millions of computers all over the world, connected to the Internet, to communicate and exchange digital data with other computers also coupled to the Internet. Once a computer is coupled to the Internet, a wide variety of options become available. Some of the myriad functions possible over the Internet include sending and receiving electronic mail (e-mail) messages, browsing different web sites, downloading and / or uploading files, etc. In the past, activities over the Internet were limited due to the relatively slow connection speeds of dial-up modems over standard telephone l...

AI Technical Summary

Benefits of technology

[0008]The present invention pertains to a metropolitan packet transport ring network (MPTR) that efficiently allocates bandwidth to users in accordance with their respective required QoS (quality of service). To addresses the ever-increasing need for ever increasing amounts of data transport bandwidth, the Internet backbone is continually being upgraded to substantially increase its data transfer bandwidth. New technologies are rapidly being introduced which increase the data transport capacity of the Internet backbone by several orders of magnitude. The present invention provides a method and system for distributing this bandwidth to end users in a manner that is cost-effective and which allocates bandwidth on the basis of the user's required QoS.

[0012]In so doing, the present invention solves the strict priority problem common to ring topology networks. Ring topology networks are known to have an up-stream strict priority problem wherein upstream nodes (e.g., one or more upstream MPS's) have larger amounts of available bandwidth in the communications channel in comparison to downstream nodes. The present invention solves this problem by throttling the rate at which data is transmitted from the upstream MPS's with respect to the rate at which data is transmitted from the downstream MPS's to implement a weighted fair bandwidth utilization of the communications channel. Thus, the weighted fair bandwidth utilization scheme is implemented without resorting to inefficient circuit switching approaches such as TDM or fixed wavelength assignment, which waste bandwidth when a flow is idle and which can introduce excessive buffering delay.

Problems solved by technology

In the past, activities over the Internet were limited due to the relatively slow connection speeds of dial-up modems over standard telephone lines.

However, there is a problem with distributing the bandwidth of this new fiber optic network to end users.

Essentially, this next-generation information superhighway has no real, sufficient entrance or exit ramps.

Although this process is standard and well-accepted, it suffers from several drawbacks.

Due to traffic congestion, network availability, routing conditions, and other uncontrollable external factors, this process is highly unreliable and unpredictable.

As such, the reliability of traditional LAN switches and routers is limited to approximately 80 percent.

Consequently, it is virtually impossible to provide any kind of quality of service (QoS) using traditional LAN switches and routers.

For real-time applications such as video on demand, HDTV, voice communications, etc., dropped packets or late-arriving packets can seriously disrupt or even destroy performance.

For example, a e-commerce or business web site may lose critical revenue from lost sales due to customers not being able to access their site during peak hours.

However, these mechanisms are all extremely expensive to implement.

Although TDM enables QoS, it is costly to implement because both the transmitter and receiver must be synchronized at all times. The circuits and overhead associated with maintaining this precise synchronization is costly.

Furthermore, TDM based networking technologies are highly inefficient in that if a user does not transmit data within his dedicated time slot, that time slot goes empty and is wasted.

In other words, TDM employs a use-it-or-lose-it approach whereby unused bandwidth is totally wasted; unused bandwidth cannot be reallocated to a different user.

Although the Internet backbone is being substantially overhauled to substantially increase its bandwidth, there is no mechanism in place today for distributing this bandwidth to end users that is cost-efficient yet which also has the ability of providing QoS.

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